78536657 has 2 divisors, whose sum is σ = 78536658. Its totient is φ = 78536656.

The previous prime is 78536641. The next prime is 78536659. The reversal of 78536657 is 75663587.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69288976 + 9247681 = 8324^2 + 3041^2 .

It is an emirp because it is prime and its reverse (75663587) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78536657 - 2⁴ = 78536641 is a prime.

Together with 78536659, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78536659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39268328 + 39268329.

It is an arithmetic number, because the mean of its divisors is an integer number (39268329).

Almost surely, 2^78536657 is an apocalyptic number.

It is an amenable number.

78536657 is a deficient number, since it is larger than the sum of its proper divisors (1).

78536657 is an equidigital number, since it uses as much as digits as its factorization.

78536657 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1058400, while the sum is 47.

The square root of 78536657 is about 8862.0910060775. The cubic root of 78536657 is about 428.2435235239.

The spelling of 78536657 in words is "seventy-eight million, five hundred thirty-six thousand, six hundred fifty-seven".